1. Field of Invention
The present invention relates to a zoom lens, and particularly to a low-cost zoom lens.
2. Description of the Related Art
Along with the development of modern video technology, image devices, such as digital video cameras (DVCs), digital still cameras (DSCs) and the like, have been broadly used by the public. One of kernel components in the image devices is a zoom lens, by which an image can be clearly focused on a charge coupled device (CCD) for imaging by the optical zooming of the zoom lens. Thus, the optical quality of the zoom lens is closely linked to the image quality. In the competitive market, manufacturers strive for improving the quality of the zoom lens and reducing the manufacturing cost thereof so as to advance the product competitiveness of their own.
Referring to FIGS. 1A and 1B, FIGS. 1A and 1B are schematic structure drawings of a conventional zoom lens with different zooming magnification. FIG. 1A corresponds to the mean position of the zoom lens, while FIG. 1B corresponds to the tele-end position of the zoom lens. The conventional zoom lens 100, disclosed by U.S. Pat. No. 6,718,132, includes a first lens group 110, a second lens group 120, a third lens group 130, a fourth lens group 140 and a fifth lens group 150. The five lens groups comprise three pieces of lenses 112, three pieces of lenses 122, one piece of lens 132, four pieces of lenses 142 and one piece of lens 152, respectively; that is, the zoom lens 100 is constructed by twelve pieces of lenses in total.
As described, when the magnification of the zoom lens 100 changes from the wide-end to tele-end (as shown in FIG. 1B), or from the tele-end to wide-end, the second lens group 120, the fourth lens group 140 and the fifth lens group 150 in the above-mentioned five lens groups move simultaneously for increasing or reducing the magnification. It can be seen that the mechanism of the zoom lens 100 is designed as an interlocked device so that the above-mentioned the second lens group 120, the fourth lens group 140 and the fifth lens group 150 move simultaneously. Thus, the mechanism is relatively complex, and the overall size of the zoom lens can not be reduced, causing the production cost to be increased.